Suspension devices of this kind for vehicle seats are known from the prior art, wherein the upper suspension part, the lower suspension part, the first and the second swivelling connector form a parallelogram, so that the upper suspension part is parallel to the lower suspension part even in the case of a spring movement. The suspension devices preferably comprise a spring for the suspension of the vehicle seat, wherein the extension force of the suspension device can be adjusted by tensioning the spring.
However, when a relatively heavy driver sits down on the vehicle seat and wants to adjust the extension force according to his weight, he has to significantly increase the pretensioning of the spring which requires a considerable amount of force and also the adjustment cannot be performed rapidly.